Referring to FIG. 1 and FIG. 2, FIG. 1 is a schematic view of a passenger boarding bridge, and FIG. 2 is a principle schematic view of an existing passenger boarding bridge. The existing passenger boarding bridge generally includes three tunnels that are sleeve-connected with one another in turn. The three tunnels are a tunnel A 21, a tunnel B 22, and a tunnel C 23, respectively. The tunnel A 21 is hinged to the rotunda 1. The rotunda 1 is fixed on the ground by a column under the turntable 1. The tunnel C 23 is connected to a lifting column 3. The lifting column 3 is connected to a horizontal drive unit 4. The horizontal drive unit 4 drives the tunnel C forward or backward. The tunnel B 22 is sleeved between the tunnel A 21 and the tunnel C 23.
As shown in FIG. 2, a first movable pulley 221 and a second movable pulley 222 are fixed on the bottom of the tunnel B 22. The retracting wire rope 51 has one end fixed to a tailing end of the tunnel A 21, the other end fixed to a tailing end of the tunnel C 23, and a center portion passing through the second movable pulley 222. The tunnel A 21, the tunnel B 22, the tunnel C 23, the retracting wire rope 51 and the second movable pulley 222 form one set of movable pulley mechanism. The tensile wire rope 52 has one end fixed to a leading end of the tunnel A 21, the other end fixed to a tailing end of the tunnel C 23, and the center portion passing through the first movable pulley 221. The tunnel A 21, the tunnel B 22, the tunnel C 23, the tensile wire rope 52 and the first movable pulley 221 form the other set of movable pulley mechanism. It is realized that the tunnel B 22 and the tunnel C 23 synchronous move through the two sets of movable pulley mechanisms at the three tunnels.
The passenger boarding bridge may be used in the airport for passengers to board on the airplane. After the tunnel C 23 docks with an aircraft, the passenger can enter the passenger boarding bridge through the turntable 1, then pass through the tunnel A 21, the tunnel B 22 and the tunnel C 23 in turn, and finally enter the airplane. Of course, the passenger boarding bridge may also be installed on ferry ports for passengers to board on a ship. Thus, the passenger boarding bridge may also be called a boarding bridge or other names.
In use, the retracting wire rope 51 and the tensile wire rope 52 may be broken, and the passenger boarding bridge is not in a horizontal state under many circumstances, if the retracting wire rope 51 or the tensile wire rope 52 is broken, the tunnel B 22 will move uncontrolledly which results safety hazards. It is necessary to be able to brake the tunnel B 22 under the circumstance that the wire rope is broken, in order to ensure the safety of personnel in the tunnel. The existing tunnel braking system has a complicated structure and low reliability.
It should be noted that the Background portion contains the contents which are merely used to reinforce understanding of the background technology of the present disclosure, and thus may include information that does not constitute the prior art as already known by an ordinary person skilled in the art.